The present invention refers to a method for milking an animal by means of a milking machine according to a milking process being determined by a number of adjustable parameters defining the intensity of the milking process. Furthermore, the invention refers to a device for milking an animal, comprising a milking machine arranged to permit milking of the animal according to a milking process being determined by a number of adjustable parameters defining the intensity of the milking process.
At many milking farms, the animals are milked more frequently today than previously. Frequent milking means relatively short milking intervals, i.e. the time period from one milking operation to the subsequent milking operation. In some cases, the milking interval is too short to enable a secure and complete milking of the animal, an appropriate stimulation and a satisfactory teat treatment. In particular, after a relatively short milking interval a long time period may be required between the attachment of the milking member to the teats and the milk let down. Furthermore, there is a risk of a too early removal of the milking member from the teats and that the teats are subjected to unnecessary stresses.
In voluntary milking systems, where the animals may walk about freely and visit the milking stall when they desire, the length of milking interval is less uniform than in traditional milking systems and occasionally the milking interval may be only two or three hours.
DE-A-13807256 discloses a method of milking. The method includes a continuous measurement of the milk flow. Changes in the milk flow are stored and used to control the milk intensity.
The object of the present invention is to remedy the problems caused by varying milking intervals.
This object is obtained by the method initially defined, which comprises the steps of:
determining for the animal the value of a variable related to the time period from at least one first milking operation to a following second milking operation;
milking the animal during the second milking operation by means of the milking machine; and
adjusting in connection with the second milking operation of the animal at least one of said parameters in response to said determined value.
By determining the value of a variable related to the time period between two milking operations, for instance the length of the time period, and by adjusting one of said parameters, it is possible to adapt the second milking operation to the length of the time period from the first milking operation, which may be the immediately previous milking operation or any preceding milking operation. In the latter case, said determined value may thus be based on a series of short milking intervals, for instance. By the expression xe2x80x9cintensity of the milking processxe2x80x9d is meant the characteristic performance of the milking process in a broad sense. Consequently, the intensity is defined by a number of parameters including the time period of the milking process, the time period and the intensity of the preceding stimulation of the teats, other possible pretreatments of the teats such as cleaning, the milking vacuum level, the upper and lower levels of the pulsation pressure in the pulsation chamber, the pulsation frequency, the pulsation ratio, etc. Another word for milking intensity is the aggressiveness of the performance of the milking process.
According to a preferred embodiment of the invention, the adjustment of at least one of said parameters is such that the second milking operation is performed in a less intensive manner when the time period is relatively short and in a more intensive manner when the time period is relatively long. The advantage of such a performance of the second milking operation is a more gentle treatment of the teats, especially when the preceding milking interval is short, which reduces the risks for injuries on the teats and which may result in a higher milk yield.
According to a further embodiment of the invention, the adjustment is performed in an automatic manner. Moreover, the determining of said value may also be performed in an automatic manner. It is considered that the method according to the present invention is suitable for being performed in such an automatic manner, by utilising a database storing facts and parameters about the individual animals and offering the possibility to store the value of said variable, and by utilising control means for the adjustment of different milking machine parameters and the time points for different measures, such as terminating the stimulation period or initiating removal of the teatcups. Consequently, said adjustable parameters may include at least one of the milking vacuum level, the pulsation frequency, the duration of the preceding teat stimulation, the pulsation ratio, and the point of time for the removal of the teatcups.
According to a further embodiment of the invention, the adjustment of the milking vacuum level is such that the milking vacuum level during the second milking operation is relatively low when the time period is relatively short and relatively high when the time period is relatively long. Consequently, the milking intensity may be reduced by reducing the milking vacuum level (i.e. a relatively high pressure) during the second milking operation when the milking interval from the preceding milking operation is relatively short and by increasing the milking vacuum level (i.e. a relatively low pressure) when the milking interval is relatively long.
According to a further embodiment of the invention, the adjustment of the pulsation frequency is such that the pulsation frequency during the second milking operation is relatively low when the time period is relatively short and relatively high when the time period is relatively long. Consequently, a high milking intensity is obtained by a high pulsation frequency and a low milking intensity is obtained by a low pulsation frequency.
According to a further embodiment of the invention, the adjustment of the preceding teat stimulation is such that the stimulation period during the second milking operation is relatively long when the time period is relatively short and relatively short when the time period is relatively long. When the milking interval between subsequent milking operations is relatively short, a longer stimulation period is normally required to obtain milk let down.
According to a further embodiment of the invention, the adjustment of the pulsation ratio is such that the pulsation ratio during the second milking operation is relatively low when the time period is relatively short and relatively high when the time period is relatively long. Consequently, a low milking intensity is obtained by a low pulsation ratio and a high milking intensity is obtained by a relatively high pulsation ratio.
According to a further embodiment of the invention, the adjustment of the time period for the removal of the teatcups is such that the teatcups are removed at a relatively early point of time when the time period is relatively short and at a relatively late point of time when the time period is relatively long.
According to a further embodiment of the invention, the second milking operation is the next subsequent milking operation of the first milking operation. Consequently, the determined value is based on the immediately preceding milking interval.
The object mentioned above is also obtained by the device initially defined, which comprises
a milking machine arranged to permit milking of the animal according to a milking process being determined by a number of adjustable parameters defining the intensity of the milking process,
determining means for determining for the animal the value of a variable related to the time period from at least one first milking operation to a following second milking operation, and
control means arranged to adjust at least one of said parameters of the milking machine in connection with the second milking operation of the animal at least one of said parameters in response to said determined value.
By such a device, the method of adjusting the parameters with regard to the preceding milking interval may be realised in a reliable manner. Preferred embodiments of the device according to the invention are defined in the dependent claims 13-15.